As is known, cast metal pieces for machines, for example turbine blades for gas turbines, are provided with information elements in order to be able to unambiguously identify the cast pieces as part of servicing or cleaning work or in the case of guarantee claims. A number of technical aspects must be taken into account when attaching information elements of this kind. On the one hand, the information elements must not cause interference or be damaged during subsequent use of the cast piece, and on the other, it must be ensured that it is impossible or at least very troublesome to falsify or corrupt the information elements retrospectively. The aim must be to store the information so securely that a financial gain that may possibly be fraudulently obtained by falsifying the information elements is negated by the high falsification effort necessary, so that accordingly falsification is not worthwhile.
Publication DE 102 07 279 discloses a method for producing a gas turbine blade in which a part identification number is embossed directly into the surface of the gas turbine blade by appropriate shaping of a mould. The corresponding surface section of the gas turbine blade thus forms an information element, which carries the part identification number as information.
U.S. Pat. No. 1,561,427 discloses a method for inscribing a cast piece in which characters made from a material with a higher melting temperature than the melting temperature of the cast piece are cast into said cast piece when it is produced.
U.S. Pat. No. 4,161,830 discloses a method for inscribing a cast piece. With this method, characters made from a heat-resistant material with a dovetail shape—viewed in cross section—are each bonded to a holding magnet. The resulting units are each fixed to the wall of a mould, the holding forces being produced by the holding magnets. The characters are then cast into the cast piece by filling the mould with a casting material.